1. Field of the Invention
This invention relates to a system for automatically opening or closing a slide-type opening-closing section provided on a vehicle, and more particularly to a technique effective for being applied to a slide-type door (hereinafter referred to as a "slide door") provided on a side portion of a wagon car, one-box car and the like.
2. Statement of the Related Art
In vehicles such as motor cars, there has heretofore been provided an opening-closing section everywhere in a sliding manner such as a window, a sun-roof, a door and the like. Particularly, in the vehicles such as wagon cars and one-box cars, there are often found ones with which a slide door being provided on the side portion thereof to get on and off, and to load and unload easily. However, with this slide door, although a relatively large opening can be secured without taking a space for opening or closing the door, the slide door tends to be large and opening or closing of the door is liable to be heavy. For this, there have heretofore been cases where it is difficult for women and children to easily open or close the door. In particular, there have been such problems that, when the vehicles stop on a sloping road, it is difficult to open the door or the door is closed abruptly. Then, under the circumstance where one-box cars and the like are increased for family use, there is a trend that there are introduced vehicles equipped with systems for automatically opening or closing a slide door, in which women and children can easily open or close the door, and the number of such cars is increasing. Furthermore, if the system for automatically opening or closing the door is provided, then, the slide door can be remote-controlled even when a hand cannot reach from a driver's seat, so that there are quite a few request for mounting the automatic opening-closing system from this viewpoint of handiness.
The above-described system for automatically opening or closing the door has a construction as shown in FIG. 8 in general. A slide door 1 is provided on one side of a vehicle body 2 and moved in the longitudinal direction of the vehicle body 2 to be opened or closed. In this case, the slide door 1 is secured to a wire 4 through a center roller assembly 3, whereby the slide door 1 is operated to open or close by this wire 4. Furthermore, the vehicle body 2 is provided thereon with a slide rail 5, whereby the center roller assembly 3 is guided and moved by the slide rail 5. A curved portion 5a is formed on the front side of the slide rail 5 and the center roller assembly 3 is guided by this curved portion 5a, whereby the slide door 1 is closed in a state of being flush with the side surface of the vehicle body 2 as indicated by one-dot chain lines.
On the other hand, the wire 4 is guided by a slide actuator 7 through a pulley assembly 6a and 6b. FIG. 9 shows the outline of construction of this slide actuator 7. The wire 4 is wound by a drum 10 which is driven by a motor 9. In this case, by the rotating direction of the drum 10, it is determined that which side of the wire 4 is wound, whereby the moving direction of the slide door 1 is determined. Then, along with the driving of the drum 10, the slide door 1 is guided by the slide rail 5 and moved thereon while the slide door 1 is pulled by the wire 4. The slide actuator 7 is controlled by a control unit 8 as being a control means incorporated therein with a computer and the like, and controls of the countering to a clamping and the like, which will be described hereunder, are performed by this control unit 8. Furthermore, transmission of a driving force from the motor 9 to the drum 10 is performed through gears 14a to 14d.
Next, tensioners 11a and 11b are provided on a former stage of the drum 10, whereby looseness of the wire 4 is removed to maintain the tensile force thereof within a predetermined range all the time. In this case, the tensioners 11a and 11b are provided with fixed pulleys 18a, 18b and moving pulleys 12a, 12b. The wire 4 starts from the fixed pulleys 18a and 18b, and it is guided around the moving pulleys 12a and 12b, and thereafter, wound by the drum 10. Furthermore, the tensioners 11a and 11b are energized by tension springs 13a and 13b in a direction for lengthening a path, in which the wire 4 is drawn around. With this arrangement, when the tensile force of the wire 4 is loosened, the moving pulleys 12a and 12b are automatically moved in the direction for lengthening the path of the wire 4, whereby the looseness of the wire 4 is removed, so that a predetermined tensile force can be maintained. Accordingly, the looseness of the wire 4 occurring immediately after the operation of the drum 10 and the looseness due to the load fluctuations, which occurs when the center roller assembly 3 enters the curved portion 5a of the slide rail 5, are absorbed by the movement of the moving pulleys 12a and 12b.
Now, in the system for automatically opening or closing the slide door, in order to protect crew members, there is required a safety countermeasure against the clamping of people, load and the like during the opening or closing of the slide door. In general, in the system for automatically opening or closing the slide door, there are often found such operations that the slide door 1 is moved from full opening to full closing or from full closing to full opening when a switch is turned on. Accordingly, when getting on or off is performed after the switch operation, there occur cases where people and load are clamped between the slide door 1 and the vehicle body 2 at the time of closing the slide door 1. Furthermore, when the slide door 1 is opened, there are cases where people and the like are clamped between an end of the slide door 1 and an external obstacle. It is essential for the system for automatically opening or closing the slide door to provide the safety countermeasure against the clamping.
In this case, it is the most important question that how the occurrence of clamping can be detected. For this, it is most efficient to provide a sensor for sensing the clamping on the slide door 1 itself. However, since it is known case by case that in what position the clamping has occurred, it cannot be clearly determined that at what position of the slide door 1 the sensor should be mounted. Furthermore, from the viewpoint of the layout of the vehicle, the slide door 1 is one which is an electrically separated equipment, so that it is necessary to add a special equipment for transmitting a detection signal from the sensor. Further, there are methods for physically sensing strain occurring in the slide door 1 and extension and the like of the wire 4 due to the clamping. However, all of these methods have problems regarding the position of mounting a strain gauge and noises thereof, so that it is substantially difficult to measure these. Then, in the conventional system for automatically opening or closing, by detecting a change in the number of rotation of the motor, which occurs due to the clamping, controls such as stopping, reverse rotation and so forth of the motor 9 have been performed on the basis of the change in the number of rotation.
Here, in the conventional system for automatically opening or closing, the change in the number of rotation of the motor 9 is measured in the following manner. Firstly, as shown in FIG. 9, a magnet 15 is disposed on the same shaft axis as an output shaft 9a of the motor 9, and a Hall element 16 is provided at a position close to the magnet 15. In this case, for example, 10 poles are magnetized in the magnet 15. That is, changes in the magnetic poles take place 10 times per rotation of the motor. Then, the change in the magnetic poles is seized as pulses by the Hall element 16, whereby the change in the number of rotation is measured due to the change in the interval of pulses. For example, when a man is clamped by the slide door 1, the wire 4 is stretched fully, whereby the load to the motor 9 is increased, the number of rotation is decreased and the motor 9 is stopped soon. At this time, the interval of the pulses emitted from the Hall element 16 is enlarged abruptly, whereby the change in the number of rotation is detected. When this change exceeds the change normally expectable as in the case where there has occurred the entrance into the curved portion 5a for example, i.e., when the number of rotation is changed abruptly, it is concluded that the clamping has occurred and the motor 9 is rotated reversely to dissolve the clamping.
Now, as a mechanism having a construction similar to the system for automatically opening or closing the slide door, there is found a power window system as shown in Patent Application Publication No. 32088/1971. This power window system is one, in which a window that is one of the opening-closing section of the vehicle is automatically opened or closed, and, for which it is naturally required that a safety countermeasure against the clamping is taken up.
Here, as shown in FIG. 10, a window pane 51 is secured to a wire 53 through a clamp 52, and this wire 53 is wound by a driving reel 55 which is driven by a motor 54, whereby the window pane 51 is moved up or down. In this case, if clamping occurs, then, a reel 56 is pulled downwardly, whereby a rocking rod 57 compresses a compression spring 58, and is rocked about a pin 59 in a counterclockwise direction. With this arrangement, a sensing microswitch 60 secured to the rocking rod 57 is moved toward a fixed rod 61, and the microswitch 60 is pressed by the fixed rod 61 to close a circuit for reversely rotating the motor 9, so that the clamping can be dissolved.
However, a conventional system for sensing a clamping like this presents such a problem that, firstly, with one, in which the clamping is sensed due to the change in the number of rotation of the motor, it takes long time before a change appears in the number of rotation of the motor from the time of occurrence of the clamping, whereby quite a long time lag occurs before the action of dissolving the clamping is started, and hence, the load applied to people who is clamped and the like is liable to exceed a standard aiming at less than 100N (FMWSS118).
Here, as shown in FIG. 11, the change in the number of rotation of the motor appears after transmitting the influence due to the clamping to a multiplicity of parts. That is, firstly, the clamping at the slide door 1 is transmitted to the slide rail 5 and the wire 4 through the center roller assembly 3 (S1-S4). Subsequently, as the wire 4 is wound up, the tensioners 11a and 11b are moved to remove the looseness of the wire 4 (S5), and finally, the wire 4 is stretched fully, whereby the load is transmitted to the drum 10 (S6). Then, the load, which was transmitted to this drum 10, is transmitted to the motor 9 through gears 14a to 14d (S7 and S8). With this arrangement, the clamping appears as a change in the number of rotation of the motor 9 for the first time, and the change is detected, whereby a command for reversely rotating the motor 9 is issued by the control unit 8 (S9).
As described above, according to the conventional system, stage of S1-S9 should be passed through before the motor 9 is reversely rotated from the time of occurrence of the clamping, whereby the time lag before the clamping becomes long. That is, various parts cause losses in the system of sensing the clamping, whereby response to the clamping is liable to be slow.
On the other hand, in the power window type system for sensing a clamping as shown in FIG. 10, the sensing microswitch 60 is operated in response to the movement of the tensioners 11a and 11b as shown in FIG. 9, so that the time lag can be lessened as compared with the above-described case. However, in the system for automatically opening or closing the slide door, the load is fluctuated depending upon the position of the slide door 1 due to the friction and the like of the curved portion 5a, whereby the positions of the tensioners 11a and 11b are changed. For this, there cannot be adopted a mechanism for sensing a clamping by an absolute value of a change in the position of the reel 56 as in the power window which is low in the load fluctuations. In this case, with the power window, unless there is an abnormal state such as a clamping, a change in the position of the reel 56 is small as compared with the case of the slide door, and, if the position of the reel 56 is changed and exceeds a value of change occurring during the transient state at the time of starting, then, it can be concluded that an abnormal state has occurred. Accordingly, in the power window, it is possible to determine the clamping using an absolute value by providing a predetermined threshold value in the value of change of the position of the reel 56.
In contrast to this, in the system for automatically opening or closing the slide door, there are no load fluctuations in the straight-lined portion 5b of the slide rail 5 and the positions of the tensioners 11a and 11b are not changed. However, when the center roller assembly 3 enters into the curved portion 5a, the positions of the tensioners 11a and 11b are changed. Accordingly, in the construction shown in FIG. 10, the load fluctuations at the curved portion 5a also concluded to be the clamping, so that the construction cannot counter the system which has the load fluctuations such as the slide door. In this case, it is possible that the change in the position due to the load fluctuations is expected, whereby the stroke of the rocking rod 57 is set at a large value, so that the change in the curved portion 5a is not concluded to be the clamping. However, if the stroke of the rocking rod 57 is set at a large value, then, more time is required for sensing the clamping, when it occurs actually, with the result that such a new problem that the sensing of the clamping is delayed is newly presented.